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Induction Motor
Why star point of star connected motor is not grounded?
rajakumar1985
- Sep 10th, 2009
Normally the 3 phase induction motors are not star connected. In the star connected machine, the phase voltage will be 1/ 3 times. So that the torque of the machine will be reduced. Because of this reason normally all the induction motors are having delta connected field windings.
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Motor Frequency
Motor manipulator detail is 230v 50hz frequency. If you increase frequency what will happen?Is there any need for coil protection?
vijay5586
- Oct 19th, 2009
Speed N=120f/p so if we increase the frequency the seed will also increase as per our electrical stands in India we are maintaining 50Hz as the constant frequency it is better maintaining the freq...
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Phase Shifting
Why do we use phase shifting at Current Transformer?
raul10
- Apr 8th, 2009
We use phase shifting in current transformer to transfer the magnetic flux density around the core
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Sub-Station Label
Why the Substaions are labled as 11KV/33KV or 66/11KV etc instead of label with the POWER TRANSFORMERS Rating (In MVA/KVA)?
kannanvellai
- Mar 31st, 2009
All electrical equipments operated depend on voltage.In substations we can get same ratio transformers with various power ratings.Ex:400/200KV with 800MVA 315 MVAPower rat...
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Capacitor Banks on DG
Why many people not connect the APFC/Capacitors in DG circuit?
shrinirmal
- May 1st, 2009
When normal supply is 'On' that time APFC will be on, At that time it will consume current, for correcting P.F, in case of D.G will not run continously so avoid over load on D.G APFC panel not connected.
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Motor Starting
The single phase induction motor starts with two phases(Using capacitor). Why can't the three phase induction motor starts with two phase?
jeet29
- Jun 8th, 2009
For the starting of a single phase motor we need two different fields and the resultant of both the fields works as the operating field revolving the motor in the direction of strong field (for more...
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APFC Panel Circuit Fuse Units
Why We should use only Fuse units in APFC Panel circuit instead of ACB/MCCB/MCB?
bittu123
- Nov 8th, 2011
Automatic power factor correction panels will control the load power factor by sensing various available parameters like Current, Power Factor, and KVAR.... Since sensing units are already there whi...
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Floting Earth
What is meant by Floting Earth? What will happen if we use regular earthing instead of floting earth and Where do we have to use only floting earth.
sn_rangari23
- Sep 28th, 2009
Floating Earth used in High Voltage equipment for high voltage Pit-Earth Test carried out for Transformer, Generator, Compressor, cables etc. for checking the condition?of moister & dryness of the cable.?
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Measure DC Current
How can we measure the DC current directly?
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Circuit Breaker
What is single and 2 pole circuit breaker?
OLIELCTRICAL
- Aug 18th, 2009
Single pole only connect in phase incoming and out going line the load. Single pole holes top one & bottom one. max rating - 25 amps. Two pole?connect in phase & neutral. 2 holes top two & bottom two. max rating - 32. example mcb.
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Voltage Standing Wave Ratio
List the basic ways of determining the voltage standing wave ratio in a transmission line.
naveed_ahmed
- Jul 13th, 2009
VSWR is a ratio of? Vmax to Vmin or Imax by?Imin?which can be theoretically?determined by using smith chart or practically determined by using vswr meter.
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Harmonics Deduction
How can we control or deduct harmonics?
veerateja
- Jun 18th, 2010
By improving the power factor by using capacitor or by synchronous condenser the harmonics can be reduced.If three phase is used the harmonics can heat the neutral wire ,so it is better to keep the diameter of neutral wire more than the other phases.
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Insulation Value
What is the thumb rule for insulation value in bus bars, phase to phase and phase to earth for 11 & 33 kV system?
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Network Synthesis
Why the roots of the network function are +ve?
deepanshu_jadon
- Mar 10th, 2010
Roots of the network function should be negative for the stability of the function.For positive roots network function is unstable.
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Insulation Value
What is the thumb rule for insulation value in bus bars, phase to phase and phase to earth for 11 & 33 KV system?
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Insulation resistance for of generator
What is the value of insulation resistance between Neutral and earth of a 65 KVA Generator?
csbalu
- Aug 29th, 2009
First of all let me clarify this,Insulation value does not depend on KVA rating of the Generator.It depends only on the rated voltage of the Generator.The insulation resistance is measured between the...
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Insulation Resistance Testing
When we apply the DC voltage thro' the digital Megger to test the IR value for cable/motor winding etc., we can see the digital display of the test equipment showing more than the applied voltage (for eg. if we select 500V dc, we can see 526V dc in the display) Why?
sinhasunilk
- Jul 3rd, 2010
When we measure IR value, we measure resistance of insulation of the circuit either w.r.t earth or w.r.t. to other phase.The digital display is resistance between the ckt and earth, not the voltage. I...
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Specific Gravity of Fully Charged Lead Acid Battery
What is the Specific Gravity of Fully charged Lead Acid Batteries?
prabhat.gaurav
- Dec 8th, 2009
For Fully charged bateery specific gravity is 1.265 and its specific gravity starts decreasing with the discharging of battery. and for fully discharged it's spec. garvity is around 1.120
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